The work proposed is the study of the mechanism whereby liver cytoplasmic G6PD activity levels are controlled by dietary fat and carbohydrate. A new model for this dietary regulation is being proposed which does not involve induction of enzyme synthesis, but does involve irreversible inactivation by fat metabolites. This year's work will be principally devoted to the study of this model and to the nature of the inactivated enzyme. BIBLIOGRAPHIC REFERENCES: Mack, Donald O., Watson, Julia J. and Johnson, B. Connor. Effect of Dietary Fat and Sucrose on the Activities of Several Rat Hepatic Enzymes and their Diurnal Response to a Meal. J. Nutr. 105, 701-713 (1975); Mack, Donald Orville, Watson, Julia J. and Johnson, B. Connor. Regulation of Glucose-6-phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase in the Meal-fed Rat. J. Nutr. 105, 714-717 (1975).